bbbb bbci bbrc bcbc bccc bcci bcor bcru bcuc bibb bibi bibo bicc bici bico bio- bioc bioi biou birb biri biro birr biru bobb bobi bobo bobu boco bocu boi- boii boiu boob booc boor bor- bori boro borr boru bour brcb bric brio brob broc broo bror brou brrr bruc bubb bubi bubo bubu bucc buci buco bucu buic buir buiu bur- burb buri buro burr buru c-bo cbbc cbcc cbcr cbcu cbir ccbc cccb cccc ccci cccu ccic ccii ccir ccob ccoc ccrc ccri ccuc cibc cibi cibo cicc cici cico cicr cicu ciii ciob cior cirb circ ciri ciro cirr ciuc cobb cobi cobo cobu coco cocu coir coob cor- corb corc cori coro corr coub cour crbc crbu crcc crcr crib cric criu crob croc croo cror crub cub- cubb cubi cucc cuci cui- cuir curb curi curo curr ibrc ibri ibro icbc iccb iccc icci icco iccr iccu icoc icor icrc icrr icru icub iiii iiio iioi iioo iirc iiuc iobi ioci ioii ioio iooi iooo iori ircc ircu iri- iric irio irob iroc irrc irri iucc iuiu obbo oboi obor obri obro ocbc occc occi ocro ocrr ocur oici oiii oobi oocr oooo orbb orbi orbo orbu orci orco ori- oric orio oro- oror orri orro orub oucc ouii ouir our- ouro ouu- rbbb rbbr rcbc rcbo rccb rccc rcic rib- ribo ribu ricc rico riou riri rob- robb robi robo robu rocc roco roio roir roiu roob rooi roor rorc rori roro roru roub rrrr rubb rubi rubu ruci rurc ruri ruro ruru ubbi ubbo ubic ubii ubir uboc ucbc ucci ucio ucrc uirr uocc uor- urbi urci urib uric uriu uro- uroo urri urur uuoc uuri uuuu